The present invention relates to disc drive suspension systems and particularly to a head gimbal assembly in which the hinge region of the head gimbal assembly is unbent in its free state.
The head gimbal assembly generally includes a base plate, a hinge region, a load beam, a gimbal, a slider and a transducing head. The base plate and proximal region of the load beam are attached to a mounting block of an arm assembly.
Typically, the head gimbal assembly is pre-bent at the hinge region to place the load beam into an angled position. This is known as “forming a preload bend.” Therefore, in its free state, prior to attachment to an actuation assembly, the head gimbal assembly has a convex appearance after the preload bend has been formed. This preload bend allows a specific amount of preload to be applied to the slider when the head gimbal assembly is loaded onto the media and in use. When loaded, or placed on the magnetic media, the hinge region flattens and the load beam is then relatively parallel to the magnetic media. In its loaded state, the preload, in combination with positive and negative pressures created by the slider's air bearing surface, allows the slider to fly at the proper clearance from the media.
Generally, head gimbal assemblies are shipped in the pre-bent free state where the fragile bent portion is susceptible to shipping and handling damage. This creates an increase in cost as the damaged head gimbal assemblies require retooling or scrapping.
Another problem with preloading is that the specific bend in the hinge region may not be consistently repeatable. The head gimbal assembly is very sensitive to where and how it is bent. During manufacturing special care must be utilized to ensure that the hinge region is properly bent. A change in the bend could change the force that is applied to the slider and therefore change the ability of the slider to fly over the magnetic media.
Therefore, there is a need in the art for a load beam less susceptible to damage from transportation handling, but with the ability to still provide the additional downward negative force necessary for the slider to properly fly over the media.